可靠性强化试验技术在某型伺服作动器研制中的适用性探索

目的探索可靠性强化试验技术在典型机电液一体化产品伺服作动器研制过程中的适用性。方法以某型伺服作动器为研究对象,从故障激发的角度对可靠性强化试验技术的应用进行可行性分析,在响应调查和应力分析的基础上,结合产品的工作特点设计适用于该类伺服作动器的可靠性强化试验方案,包含低温步进应力试验、高温步进应力试验、快速温度循环试验10个循环、振动步进应力试验(包含气锤式三轴向六自由度超高斯随机振动方式及电磁振动台随机振动方式)及综合环境应力试验5个循环,并依此进行试验。结果在快速温度循环试验及综合环境应力试验过程中,均有效地激发出了产品的漏油故障,与相似产品外场暴露的漏油故障模式相吻合。结论可靠性强化试验技术可有效地应用于典型机电液一体化产品伺服作动器的研制过程,设计的可靠性强化试验方案可有效地激发外场出现频率较高的故障,可作为该类产品研制的试验手段之一。     

包装箱用碳纤维增强复合材料贮存寿命研究

目的研究碳纤维增强复合材料贮存条件下的性能变化趋势和寿命评估。方法对碳纤维增强复合材料开展四个不同温度条件下的热氧老化试验,按试验周期定期取样开展冲击性能测试,对试验数据采用寿命预估方法进行处理,对材料性能进行预估。结果通过数据计算分别得到我国热带海洋、干热沙漠等典型气候条件下的碳纤维增强复合材料贮存寿命分别为17.21~35.89年。结论碳纤维增强复合材料具有较好的贮存性能,在较为严酷的热带海洋气候和给定的失效判据条件下,寿命预计为17.21年。试验和数据处理方法可以较好地预计材料的性能变化趋势和开展寿命评估。     

南昌市冬季大气PM2.5中重金属元素来源分析及健康风险评价

采集2015年南昌市冬季大气PM_(2.5)样品,利用电感耦合等离子体质谱仪(ICP-MS)测定样品中重金属(V、Mn、Cr、Co、Ni、Cu、Zn、Cd、Ba和Pb)的含量,分析重金属的分布特征和来源,并对重金属健康风险进行评价。结果表明:采样期间PM2.5浓度总平均值为(29.74±16.82)μg/m~3,其中省外办最高,武术学校最低;各重金属元素总体平均浓度从高到低次序为:ZnPbCuMnBaNiVCrCdCo。因子分析结果表明:PM_(2.5)中重金属元素的来源包括道路交通尘和冶金化工排放、机动车尾气以及混合源。健康风险评价结果显示:PM_(2.5)中Mn对人体健康存在非致癌风险,其他元素(Cr、Ba、Co、Pb、Cd、Cu、V、Zn、Ni)基本没有非致癌风险;Cr对人体有较明显的致癌风险,Cd、Ni和Co对部分年龄段的人群(尤其是成年人)存在一定的致癌风险。     

Monitoring Air Quality in Mountains: Designing an Effective Network

A quantitatively robust yet parsimonious air-quality monitoring network in mountainous regions requires special attention to relevant spatial and temporal scales of measurement and inference. The design of monitoring networks should focus on the objectives required by public agencies, namely: 1) determine if some threshold has been exceeded (e.g., for regulatory purposes), and 2) identify spatial patterns and temporal trends (e.g., to protect natural resources). A short-term, multi-scale assessment to quantify spatial variability in air quality is a valuable asset in designing a network, in conjunction with an evaluation of existing data and simulation-model output. A recent assessment in Washington state (USA) quantified spatial variability in tropospheric ozone distribution ranging from a single watershed to the western third of the state. Spatial and temporal coherence in ozone exposure modified by predictable elevational relationships ( 1.3 ppbv ozone per 100 m elevation gain) extends from urban areas to the crest of the Cascade Range. This suggests that a sparse network of permanent analyzers is sufficient at all spatial scales, with the option of periodic intensive measurements to validate network design. It is imperative that agencies cooperate in the design of monitoring networks in mountainous regions to optimize data collection and financial efficiencies.     

大气环境质量综合评价加权灰色关联模型的建立与应用

利用灰色理论建立大气环境质量综合评价加权灰色关联模型 ,运用污染贡献率确定权重系数。与其它评价模型相比 ,加权灰色关联模型还具有排序功能 ,实例表明该模型是简便有效的     

Incorporating natural capital into economy-wide impact analysis: a case study from Alberta

Traditionally, decision-makers have relied on economic impactestimates derived from conventional economy-wide models. Conventional models lack the environmental linkages necessary for examining environmental stewardship and economic sustainability, and in particular the ability to assess the impact of policies on natural capital. This study investigatesenvironmentally extended economic impact estimation on a regionalscale using a case study region in the province of Alberta knownas the Foothills Model Forest (FMF). Conventional economic impactmodels are environmentally extended in pursuit of enhancingpolicy analysis and local decision-making. It is found that theflexibility of the computable general equilibrium (CGE) modelingapproach offers potential for environmental extension, with a solid grounding in economic theory. The CGE approach may be the tool of the future for more complete integrated environment andeconomic impact assessment.     

Cumulative effect assessment in Canada: a regional framework for aquatic ecosystems

Sustainable development of the aquatic environment depends upon routine and defensible cumulative effects assessment (CEA). CEA is the process of predicting the consequences of development relative to an assessment of existing environmental quality. Theoretically, it provides an on-going mechanism to evaluate if levels of development exceed the environment's assimilative capacity; i.e., its ability to sustain itself. In practice, the link between CEA and sustainable development has not been realized because CEA concepts and methods have developed along two dichotomous tracks. One track views CEA as an extension of the environmental assessment (EA) process for project developments. Under this track, stressor-based (S-B) methods have been developed where the emphasis is on local, project-related stressors, their link with aquatic indicators, and the potential for environmental effects through stressor-indicator interactions. S-B methods focus on the proposed development and prediction of project-related effects. They lack a mechanism to quantify existing aquatic quality especially at scales broader than an isolated development. This limitation results in the prediction of potential effects relative to a poorly defined baseline state. The other track views CEA as a broader, regional assessment tool where effects-based (E-B) methods specialize in quantification of existing aquatic effects over broad spatial scales. However, the predictive capabilities of E-B methods are limited because they are retrospective, i.e., the stressor causing the effect is identified after the effect has been measured. When used in isolation, S-B and E-B methods do not address CEA in the context necessary for sustainable development. However, if the strengths of these approaches were integrated into a holistic framework for CEA, an operational mechanism would exist to better monitor and assess sustainable development of our aquatic resources. This paper reviews the existing conceptual basis of CEA in Canada including existing methodologies, limitations and strengths. A conceptual framework for integrating project-based and regional-based CEA is presented.     

一次监测值用于水质评价的研究

以2003年长江和淮河水系为例,通过计算各个评价项目的单月监测值分别与季均值和年均值的相对误差及其分布,以及水质类别相同的断面比例,认为对于旬报、月报短期水质评价,采用一次监测的数据评价水质是可靠的;对于季报和年报中、长期水质评价,采用一次监测数据评价的可靠程度较差,应采用2次或2次以上的监测数据平均值进行评价。     

地表水环境质量定性评价

针对目前缺乏统一的地表水环境质量定性评价准则的现状,根据我国主要水体的污染程度,提出了断面、河流、水系水质定性评价方法。     

Assessing protected area effectiveness using surrounding (buffer) areas environmentally similar to the target area

Many studies are based on the assumption that an area and its surrounding (buffer) area present similar environmental conditions and can be compared. For example, in order to assess the effectiveness of a protected area, the land use/cover changes are compared inside the park with its surroundings. However, the heterogeneity in spatial variables can bias this assessment: we have shown that most of the protected areas in Mexico present significant environmental differences between their interior and their surroundings. Therefore, a comparison that aims at assessing the effectiveness of conservation strategies, must be cautioned. In this paper, a simple method which allows the generation of a buffer area that presents similar conditions with respect to a set of environmental variables is presented. The method was used in order to assess the effectiveness of the Calakmul Biosphere Reserve, a protected area located in the south-eastern part of Mexico. The annual rate of deforestation inside the protected area, the standard buffer area (based upon distance from the protected area only) and the similar buffer area (taking into account distance along with some environmental variables) were 0.3, 1.3 and 0.6%, respectively. These results showed that the protected area was effective in preventing land clearing, but that the comparison with the standard buffer area gave an over-optimistic vision of its effectiveness.